My DM on has purchased and shared all the sourcebooks on D&D Beyond (including Eberron: Rising from the Last War) and I have all the content enabled on the character creation screen but still can't select Artificer as a class option.

Any ideas as to what I may be doing wrong?

Are you building that character directly in that campaign? If you are building outside of the campaign with the plan to move them in when it is complete that’s the problem. Follow the Campaign link the DM sent you and build the character ther and it should work. You will have to make sure everything is turned on again, the switches should be red. 

Ahhh that must be it. I wasn't creating the character from within that campaign. 

Thanks for the help!

Happy to be of assistance.